1. Technical Field
Various embodiments relate generally to wireless communication and more particularly to communication devices that employ beamforming antennas to support wireless communications.
2. Description of Related Art
Communication systems are known to support wireless and wireline communications between wireless and/or wireline communication devices. Such communication systems range from national and/or international cellular telephone systems to the Internet to point-to-point in-home wireless networks to radio frequency identification (RFID) systems. Each type of communication system is constructed, and hence operates, in accordance with one or more communication standards. For instance, wireless communication systems may operate in accordance with one or more standards including, but not limited to, RFID, IEEE 802.11, Bluetooth, advanced mobile phone services (AMPS), digital AMPS, global system for mobile communications (GSM), code division multiple access (CDMA), local multi-point distribution systems (LMDS), multi-channel-multi-point distribution systems (MMDS), and/or variations thereof.
Wireless communications occur within licensed or unlicensed frequency spectrums. For example, wireless local area network (WLAN) communications occur within the unlicensed Industrial, Scientific, and Medical (ISM) frequency spectrum of 900 MHz, 2.4 GHz, and 5 GHz. While the ISM frequency spectrum is unlicensed there are restrictions on power, modulation techniques, and antenna gain. Another unlicensed frequency spectrum is the millimeter wave V-band of 55-64 GHz.
60 GHz or other millimeter wave based communications systems can rely heavily on transmit and receive beamforming to improve communications range. This is due to the fact that at millimeter wavelengths, propagation path loss (which is proportional to carrier frequency) is generally too severe to allow for acceptable communication range without deploying beamforming at either or both sides of the wireless link. Therefore, systems designed to operate at 60 GHz bands can employ mechanisms to enable transmit and receive beamforming adaptation as part of normal mode of operation. Today, both mainstream standardizations for 60 GHz communications, i.e. Wireless-HD and Wireless Gigabit Alliance (WiGig), deploy methods to facilitate beamforming training and optimization. As these 60 GHz based systems rely on beamforming gain to establish and maintain a wireless link, their performance (and hence user experience) is highly dependent on the performance and accuracy of beamforming training.